1. Technical field
The present invention generally relates to a touch panel, and particularly to a capacitive-type touch panel and a touch-point detecting method thereof.
2. Description of the Related Art
With the progress of the science and technology, people's lives are closely related to various electronic devices, especially for multimedia information systems such as televisions, computers and mobile communicating systems, etc., are often used by the majority of people. Therefore, how to facilitate users to conveniently operate or carry such electronic devices has been becoming an important issue. In addition, in order to reduce the bulk of such electronic devices, touch panels have been becoming a common technology, to replace some input devices such as keyboards or mice.
Generally speaking, the touch panels are primarily classified into the resistive-type touch panels, capacitive-type touch panels, and optical-type touch panels, etc., depending on the manner of a touch point is detected. For example, the capacitive-type touch panels use a current variation caused by a capacitance generated at a touch point to detect the location of the touch point, such a detecting method is disclosed in a U.S. Pat. No. 6,297,811 in detail, the disclosure is taken as a technical reference and thus will not be repeated herein.
However, since the capacitive-type touch panels are limited by the established detecting technologies, the applications may not be effectively extended. Referring to FIG. 1, a schematic structure view of sensing lines of a conventional capacitive touch panel 10 is provided. The sensing lines E1, E2, . . . , E9 are termed as first-dimension sensing lines, and the sensing lines E31, E32, . . . , E39 are termed as second-dimension sensing lines. The first-dimension sensing lines are parallel with one another (every two adjacent first dimension sensing lines have a predetermined distance existed therebetween), the second-dimension sensing lines are parallel with one another as well (every two adjacent second-dimension sensing lines also have a predetermined distance existed therebetween). Furthermore, the first-dimension sensing lines E1, E2, . . . , E9 are arranged crossing over the second-dimension sensing lines E31, E32, . . . , E39 and so as to be arranged as an array. Capacitances of each of the sensing lines are the same, for example each of the sensing lines employs a plurality of capacitive pads 100 as sensors. The capacitive-type touch panel 10 employs a processor 12 to scan the first-dimension sensing lines E1, E2, . . . , E9 and the second-dimension sensing lines E31, E32, . . . , E39 and further to judge the location of a touch point on the capacitive-type touch panel 10 and contacted by an object according to a current caused by a capacitance formed between the object contacting with capacitive-type touch panel 10 and such a capacitive pad 100.
According to the above-mentioned detecting method, the capacitive-type touch panel 10 may easily detect the location of single touch point. However, when there are at least two touch points existed at the same time, although the processor 12 may correspondingly obtain at least two coordinate values on the first-dimension sensing lines and the second-dimension sensing lines at the same time, the processor 12 may not determine pairing relationships of the coordinate values. In other words, since the first-dimension sensing lines and the second-dimension sensing lines are scanned respectively, the processor 12 may obtain locations of at least two touch points on the first-dimension sensing lines as well as locations of at least two touch points on the second-dimension sensing lines. However, the conventional detecting method may not determine one of the locations of the touch points on the first-dimension sensing lines correspond to one of the locations of the touch points on the second-dimension sensing lines.
In view of the above, the capacitive-type touch panel 10 may not detect the accurate locations of the at least two touch points existed at the same time, which would result in the capacitive-type touch panel having many limitations in application.